Storage of volatile liquids



June 2, 1931. s. T. TREZISE STORAGE OF VOLATILE LIQUIDS Filed Nov. 2, 1929 N wm N1 -1 m w W S, :0 Q we M k m (w m F K n u Q u m m k L Q, P L 7 AT TORN EYS Patented June 2, 1931 UNITED STATES PATENT OFFICE STORAGE OF VOLATILE LIQUIDS Application filed November 2, 1929, Serial No. 404,435, and in the Union of South Africa September 19, 1929.

In the storage of volatile liquids in large sealed tanks in situations exposed to the heat of the suns rays, it is necessary to release the pressure of the evaporated gases contained therein at frequent intervals in order to minimize the risk of explosion or damage to the tank owing to the strain resulting from the expansion of the gases which leads to considerable losses of vapour.

The object of this invention is to provide means whereby such loss may be avoided.

In means for the purpose referred to, according to the invention, the vapour arising from the surface of the liquid, is condensed and the condensate returned to the tank. Means are also provided for retarding evaporation of the liquid in the tank.

One embodiment of the invention is illustrated diagrammatically in the accompanying drawing wherein 2 indicates a cylindrical tank for storing volatile liquids, e. g., petrol or the like, the highest level of the liquid being indicated by the line 3, 4. The upper portion of the tank is closed by a gastight cover 5 in which is provided an outlet pipe 6 leading to a refrigerator of any suitable kind. Conveniently, it may consist of a condensing worm or coil 7 enclosed in a jacket 8 to which a continuous stream of cold water or other suitable refrigerant is pumped through the pipe 8a.

The refrigerator jacket 8 is connected by a pipe 9 with a coil 10 situated in the space enclosed by the cover 5 of the tank 2 above coil 10 being connected with a further jacket 11 provided around the exterior of the cover 5. The outlet 12 to the jacket 11 is connected with the refrigerant-circulating system.

In use the gases generated by the evaporation of the liquid in the tank 2 are collected in the upper portion of the cover 5 and pass along the pipe 6 to the refrigerator coil 7 where they are condensed by reason of the comparatively low temperature of the refrigerant circulating through the jacket 8. The condensate is drained off at the bottom of the coil and returned to the liquid in the tank 2 by way of the pipe 13.

' the liquid level 3, 4, the opposite end of the The circulation of cold water or other refrigerant through the coil 10 and jacket 11 further assists in retarding the evaporation of the liquid in the tank 2.

It will be seen that, by reason of the low temperature of the condensing coil 7, the pressure therein is very much lower than in the tank 2, with the result that so soon as any vapour is generated in the latter, e. g., by the external heat of the suns rays, it must be drawn off and condensed in the refrigerator, thereby rendering it unnecessary to release the pressure in the tank for reasons of safety.

The cover 5 is provided with an automatic, e. g., spring balanced, inlet valve (not shown) for the purpose of admitting air to the tank when liquid is drawn off, and, if desired, there may be provided also a suitable automatic safety valve.

With reference to the drawing, it should be understood that the refrigerator is drawn to a considerably larger scale than the tank and that, in practice, the outlet of the refrigerator will be situated at a point above the level 3, 4, of the liquid in the tank.

\Vhat I claim as my invention and desire to secure by Letters Patent is 1. A storage tank for volatile liquids having means connected thereto for collecting and condensing the vapour arising from the surface of the liquid, means for returning the condensate to the tank, a refrigerator coil situated in that portion of the tank enclosed by the cover, a refrigerator jacket surrounding said cover and means for maintaining said coil and jacket at a low temperature.

2. A storage tank for volatile liquids having means connected thereto for collecting and condensing the vapour arising from the surface of the liquid, means for returning the condensate to the tank, a refrigerator coil situated in that portion of the tank enclosed by the cover and a refrigerator jacket surrounding said cover, a stream of refrigerant liquid being passed continuously through said coil and said jacket successively.

3. A storage tank for volatile liquids comprising a cover, a duct leading from said cover to a condensing coil located outside the tank, a jacket surrounding said coil, an outlet pipe connecting said coil with the tank and adapted to serve as a duct for the return of the condensate thereto, a refrigerator coil situated in that portion of the tank enclosed by the cover, a refrigerator jacket surroundin said cover and pipes connectin the jac (et surrounding the condensing (30-11 with the refrigerator coil and the refrigerator jacket, a stream of refrigerant liquid being passed continuously through said coils and said jacket successively.

In testimony whereof, I have signed my name to this specification at Durban, in the Province of Natal, Union of South Africa, this 26th day of September, 1929.

.SIDNEY THOMAS TREZISE. 

